We know it is disconcerting to folks not to have one definite, no exceptions, hands down, this is it statement about when to test for HIV. The truth is, that would not be wise because of what we know about HIV transmission. Transmission concersn two things: the health of the person being infected, and the strength of the risk factor.

You mention the presence of Hepatitis C. Yes, it's another virus that can challenge someone's immune system. If they are a normally healthy person, it won't be sufficient to stop the body from producing HIV antibodies. Now, if they are in end stage liver failure, yes, it could make a difference because that person's body is challenged in many ways.

Likewise, if the person from whom one is becoming infected is acutely ill from HIV, and has a high viral load, the risk of infection is increased.

In both of these cases, the person would be advised to have the 6 month test. For everyone else, (those normally healthy folks) the 90 days test has been proven to be valid and reliable.

Remember, we're dealing with an international epidemic and trying to give guidance for a wide range of circumstances. Sure, viruses such as Hepatitis are common in folks who also have HIV, but those same folks could be healthy, athletic people who maintain good medical management and control their viruses. If you're having sex with people who don't take good care of themselves, yes, the risk is higher that their virual load for multiple sexually transmitted diseases would be increased.

That's why we simply say, protect yourself with condoms. Take good care of yourself generally, and if you may have come in contact with the virus, consider the source and have the 90 day test. If the source is truly very high risk, we recommend the 6 month test. It's usually confirmatory of the 90 day test and really a final test to provide peace of mind.

I hope this is helpful. The science of disease transmission and testing is truly complex and these guidelines were developed to take the broadest perspective for the greatest nmumber of people.

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